Milwaukee 6155-20 5-Inch Magnum Sander/Grinder. Milwaukee 6155-20 5-inch, 12 amp grinder offers extra heavy duty grinding capability in a compact body grip ergonomic design. Use the links and tools below to Milwaukee 6155-20 5-Inch Magnum Sander/Grinder Review. And See more Milwaukee 6155-20 Grinder Specifications.